mercury lights

I replaced the dusk to dawn light on a garage. After taking down the old one and installing the new one, the light blinked once, which is what the directions said it would do. It didn't turn on at dark like it was suppose to. I tried to switch the wires to see if maybe I hooked it up wrong. Still doesn't work at night. The sensor on top has an arrow on it which I have pointed north. The brand name of the light is Regent.There is power going to the light. Is there a way to check it in the daytime? Any help is appreciated.

mercury lights

Thanks for the help. The existing wires inside the garage were the old knob and tube wires. Both had a black covering on them. I wasn't sure which one to connect the white wire from the light to. Thats why I switched them after they didn't work the first time. I installed a junction box inside the garage to connect all the wires but the ground wire from the light I just grounded to the box itself. Still not working. Thanks again.

mercury lights

Have you tried screwing the light bulb out a few turns and then back in till snug? In the daytime you should be able to cover the photo lens and force the light to come on. I really think you have an issue with the photo cell installation. What was the arrow to be used for? Isn't that to line up the photo lens dots to determine how sensitive you want the light to darkness?